Composite hydrophobic insulation textile

ABSTRACT

A composite hydrophobic insulation textile with glass fibers and a first fluoropolymer. The first fluoropolymer and the glass fibers are interspersed with one another with sufficient uniformity to render the composite hydrophobic insulation textile as hydrophobic insulation and is temperature stable up to 600 degrees Fahrenheit.

The benefit of the 20 Jul. 2016 filing date of U.S. provisional patentapplication Ser. No. 62/364,532; and of the 7 Oct. 2016 filing date ofU.S. provisional patent application Ser. No. 62/405,557; and of the 30May 2017 filing date of U.S. provisional patent application Ser. No.62/512,385 are claimed under 35 U.S.C. § 119(e) in the United States,and are claimed under applicable treaties and conventions in allcountries as well as the benefits claimed under 35 U.S.C. § 120 in theUnited States for non provisional U.S. patent application Ser. No.15/653,606 with the 19 Jul. 2017 filing and for non-provisional U.S.patent application Ser. No. 15/895,832. These references are herebyincorporated in their entirety.

FIELD

The invention pertains to a composite hydrophobic insulation textilecomprising glass fibers and a first fluoropolymer; with glass fibersinterspersed with one another with sufficient uniformity to render thecomposite hydrophobic insulation textile as hydrophobic insulation andis temperature stable up to 600 degrees Fahrenheit and comprises 60-90%glass fiber, 2-30% hydrophobic polymer and 1-10% hydrophobic inorganicparticles.

BACKGROUND

Blanket-type thermal insulation is frequently used for commercial andindustrial applications that require personnel protection or thermalinsulation. Such blankets are typically flexible, removable, andreusable to a greater or lesser degree. A drawback of most commonly-usedinsulation blankets is that they are prone to absorbing and holdingmoisture when exposed to a moisture source, whether in indoor or outdoorenvironments. Retention of moisture is undesirable because wet blanketslose much of their thermal insulation ability, they become heavier, andthey can sag. The ingress and accumulation of water not only affect theinsulating properties of the blanket, and the position of the blanketrelative to the object being insulated, but can potentially lead tounder-insulation-induced corrosion or moisture-induced corrosion on theinsulated equipment, which can affect safety and system life.

There is an unfilled need for improved, economical, hydrophobic thermalinsulation materials with improved long-term thermal performance, andresistance to corrosion when used in high-temperature, humidenvironments.

The present embodiments meet these needs.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description will be better understood in conjunction withthe accompanying drawings as follows:

FIG. 1 illustrates one embodiment of a manufacturing process forproducing the hydrophobic insulation blanket.

The present embodiments are detailed below with reference to the listedFIGURES.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Before explaining the present apparatus in detail, it is to beunderstood that the apparatus is not limited to the particularembodiments and that it can be practiced or carried out in various ways.

Specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a basis of the claims and as arepresentative basis for teaching persons having ordinary skill in theart to variously employ the present invention.

The invention relates to a composite hydrophobic insulation textilecomprising glass fibers and a first fluoropolymer; wherein said firstfluoropolymer and the glass fibers are interspersed with one anotherwith sufficient uniformity to render the composite hydrophobicinsulation textile as hydrophobic insulation and is temperature stableup to 600 degrees Fahrenheit and comprises 60-90% glass fiber, 2-30%hydrophobic polymer and 1-10% hydrophobic inorganic particles.

Several types of insulation blankets are currently availablecommercially, including those made from mineral wool, aerogels,fiberglass, and microporous insulation. Some of these materials addressor partially address water intrusion and absorption by employing a waterrepellent (hydrophobic) treatment. However, hydrophobicity in hightemperature (>400° F., 205° C.) blanket materials is rare. In mostcases, hydrophobicity decays over time or upon exposure to temperaturesin excess of 300° F. (150° C.), creating thermal inefficiency, personnelsafety risk, and corrosion issues.

Water inside an insulation material compromises insulationcharacteristics, regardless of the type of insulation material. Waterinside insulation is also a key factor in the corrosion of coveredmetallic equipment.

Mineral wools and fiberglass wools can hold large amounts of water afterthey have been submerged in water, or even without submersion afterextended exposure to water vapor/steam Hydrophobic wools, blankets,boards, or roll materials (example: Johns Manville MinWool-1200) can betreated with a water-repelling agent such as a liquid silicone emulsionor like, which can be integrated into the product during processing orsprayed onto its surface. These agents typically have a limited lifeexpectancy, depending on service conditions. They may or may not passinitial (“as new”) accepted industry standards for hydrophobicity (e.g.ASTM C 1511-15).

The invention relates to a hydrophobic needle-felted insulation blankethaving a textile-grade needle felted fiberglass blanket having a densityin the range of 4 to 15 lb/ft³ (65 to 250 g/L).

The invention includes an uniform hydrophobic fluoropolymer disposedhomogeneously throughout the textile grade needle felted fiberglassblanket without creating a higher density of hydrophobic fluoropolymernear edges of the textile-grade needle felted fiberglass blanket,wherein the fluoropolymer has a melting point over 5500 Fahrenheit.

The invention includes a non-decomposed hydrophilic opacifier uniformlydisposed through the textile grade needle felted fiberglass blanket thatreduces radiative heat flow through the finished blanket.

The finished hydrophobic needle-felted insulation blanket is (i)temperature stable up to 5500 Fahrenheit, (ii) moldable, (iii) silicadust free, and thereafter retains a selected shape and the finishedblanket will not decompose, disintegrate, or lose structural integritywhen submerged in water, and further the finished blanket comprises byweight: 60%-95% glass fiber, 2%-30% hydrophobic flouropolymer, and0.1-10% non-decomposed hydrophilic opacifier.

In embodiments, the composite does not release dust when handled or whenin use.

In embodiments, the composite hydrophobic insulation textile is athermal insulator, with a thermal conductivity k less than 0.14 Watt/m°K for at least some temperatures between 25° C. and 370° C.

In embodiments, the composite hydrophobic insulation textileadditionally includes a super-hydrophobic topcoat on at least onesurface of said composite; wherein said super-hydrophobic topcoatcomprises a mixture of a second fluoropolymer and inorganic particles;wherein said first and second fluoropolymers may be the same ordifferent; and wherein said inorganic particles comprise particlesselected from the group consisting of silica aerogel, fumed silica,precipitated silica, synthetic amorphous silica, and mixtures thereof;wherein said inorganic particles have a particle size between 0.1 to 100microns; wherein said inorganic particles have a specific surface areaof 100 m2/g or greater; and wherein said inorganic particles comprise ahydrophobic surface treatment.

In embodiments, the hydrophobic surface treatment comprises dimethylsilyl, trimethylsilyl, or other alkylsilyl moieties.

In other embodiments, the composite hydrophobic insulation textileincludes an infrared opacifier that reduces radiative heat flow; whereinsaid infrared opacifier comprises particles selected from the groupconsisting of carbon black, graphite, graphene, titanium dioxide, ironoxides, silicon carbide, zirconium dioxide, and mixtures thereof;wherein said infrared opacifier comprises 0.1% to 10% of said compositehydrophobic insulation textile by mass.

In embodiments, the glass fibers form a needle felt fiberglass blanket.

The glass fibers can be selected from the group consisting of E-glassfiber, C-glass fiber, T-glass fiber, S-glass fiber, textile-grade basaltfiber, and mixtures thereof; and wherein the diameters of said glassfibers are between 4 and 13 microns.

The glass fibers can include between 60% and 95% of said compositehydrophobic insulation textile by mass.

In embodiments, the first fluoropolymer can include a compound selectedfrom the group consisting of polytetrafluoroethylene, perfluoroalkoxyalkanes, fluorinated ethylene propylene, and mixtures thereof; andwherein said first fluoropolymer is between 2% and 30% of said compositehydrophobic insulation textile by mass.

In embodiments, the first fluoropolymer can additionally include atleast one additional, low-melting fluoropolymer with a melting pointbelow 315° C.; wherein said low-melting fluoropolymer is between 0.1%and 25% of said composite hydrophobic insulation textile by mass; andwherein said low-melting fluoropolymer improves the ability to mold saidcomposite hydrophobic insulation textile into a selected shape that isretained after molding.

The composite hydrophobic insulation textile is moldable, or wherein thecomposite hydrophobic insulation textile has been molded into andthereafter retains a selected shape.

In embodiments, the hydrophobic needle-felted insulation blanket is freeof any residual hydrophilic compounds, including glass fiber sizing, andthe surfactants that had previously been used to emulsify thefluoropolymer.

In embodiments, the textile-grade needle felted fiberglass blanketcomprises: fibers selected from the group consisting of E-glass fiber,C-glass fiber, T-glass fiber, S-glass fiber, textile-grade basalt fiber,carbon fiber, aramid fibers, and mixtures thereof; and wherein thediameters of the fibers are from 4 to 13 microns. The finished blanketcan have a thermal conductivity k measured as (Btu·in/hr-ft 2 F) of fromabout 0.26 at 75° Fahrenheit to about 1.18 at 1050° Fahrenheit. Theopacifier can include particles selected from the group consisting of:carbon black, graphite, graphene, titanium dioxide, iron oxides, siliconcarbide, zirconium dioxide, and mixtures thereof; and wherein theopacifier comprises 0.1% to 10% of the finished blanket by weight. Thehydrophobic fluoropolymer and the fibers can be interspersed with oneanother with sufficient uniformity to form a flexible matrix and renderthe finished blanket hydrophobic at temperatures at least up to 600 F.The hydrophobic surface can include a silicone, and wherein the siliconeis di-alkyl silicone fluid in the form of aqueous emulsions withparticle sizes from 100 nm to several μm; and the alkyl group has from 1to 8 carbon atoms selected from the group consisting of a methyl, aphenyl, a propyl, or a combination thereof. The fibers can include from60% to 95% by mass of the finished blanket. Additionally, thefluoropolymer can be a compound selected from the group consisting ofpolytetrafluoroethylene, perfluoroalkoxy alkanes, fluorinated ethylenepropylene, and mixtures thereof. The uniform hydrophobic fluoropolymercan be from 5 percent to 25 percent by mass of the finished blanket.

The invention is a thin, flexible, blanket insulator incorporatinghydrophobic, fumed silica particles to attain hydrophobicity to 600° F.(315° C.). Current commercial examples of insulating blankets are JohnsManville InsulThin™ HT and Microtherm® Quilted Panels but each of thesecommercial blankets has the significant disadvantage of generatingharmful to human amount of dust, substantial amounts of dust duringproduct application and fabrication. Large amounts of harmful dust iseasily released from these products when the hydrophobic woven E-glasscloth outer envelope is cut or damaged.

The present invention was conceived because commercially-availableaerogel blanket products generally meet the hydrophobicity requirementsof a well known standard, ASTM C 1511. However, aerogel blankets oftenhave excess caking resulting from their processing. Caked, excessaerogel material left on the surface can generate dust during handlingand application. This nuisance dust can cause applicators to incur addedfabrication, installation, and application precautions, with attendantincreased expense. With both microporous insulation and aerogelblankets, the generation of dust is difficult to avoid, and is a majorinconvenience for operators working with or in the vicinity of suchmaterials. In fact, the dust can be dangerous if inhaled by operators inlarge amounts.

Of interest, as comparative examples are Thermiguard™ SS D 0713Submittal Sheet (unknown date) discloses thermal blankets in which theinsulation material is a fiberglass needled mat type E fiber mat,encapsulated by PTFE-impregnated fiberglass cloth.

See also, by the inventor, L. Dill, “The Right Stuff: MaterialConsiderations,” Insulation Outlook (June 2004) describes varioushigh-temperature insulation blankets, including some made from afiberglass felt core insulation with a silicone- or PTFE-impregnatedfiberglass fabric exterior for waterproofing.

Of additional note is U.S. Patent application publication no.2011/0070789 that discloses a laminate material with layers combinedinto an insulating barrier blanket. The insulating barrier blanketcomprises a high-temperature, abrasive and puncture resistant outershell, a thermal insulation core, and an interior protective layer. Theouter shell is preferentially made of a hydrophobic or oleophobic fabriclayer, such as organic polyamide fibers or PTFE-laminated fiberglass.

A need has existed for a dust free hydrophobic insulating blanket ableto withstand high temperatures over 500 degrees Fahrenheit.

There is an unfilled need for a flexible and thin insulation materialthat is hydrophobic to temperatures of 600° F. (315° C.) for long-termuse (or higher temperatures during short excursions), that does notproduce dust during installation and use, and that is more economicalthan existing insulators and is moldable and configured to retain shapeafter molding.

The invention relates to a hydrophobic fiberglass blanket that can beused for thermal insulation that is cost-efficient to manufacture. Thehydrophobic fiberglass blanket produces little or no dust or othershedding during production, handling, and application. The final blanketdemonstrates excellent hydrophobicity to 600° F. (315° C.) for long termuse, with very good thermal insulation; comparable to that of dry, buthydrophilic (conventional) glass fiber blankets of otherwise similarneedle felt construction. Unlike conventional glass fiber blankets,which readily absorb water, the novel final blankets are highlyhydrophobic.

The invention fills the need for an economical thermal insulation devicewith excellent insulating properties, one that can interface betweenexternal ambient temperatures and internal operation temperatures up to600° F. (315° C.) for long-term use, or up to 700° F. (370° C.) forshort-term excursions. The final blanket has excellent hydrophobicity,and does not rely on a hydrophobic inorganic powder component (e.g., anaerogel) that generates excessive dust.

The invention's insulating properties are based on limiting free airmovement, as is true for most types of commercial insulation.Maintaining excellent long-term performance characteristics—thermalinsulation and corrosion mitigation (which can be assessed, for example,per ASTM C795)—is based on keeping a dry environment both in the blanketitself and on the surface of the covered substrate. Previous insulationmaterials have either not performed this task well, or they have beenoverly expensive and tend to produce excessive dust. The novel materialslimit corrosion while providing excellent thermal performance, at a costless than that of existing materials, and without generating significantamounts of dust.

The novel material is a thermal insulator whose thermal conductivityproperties lie roughly between those of an aerogel blanket, and of 4 lbdensity mineral wool board.

The novel insulation blanket meets or exceeds the water absorptionrequirements of ASTM C 1511 test protocol, the industry standard fordetermining the Water Retention (Repellency) Characteristics of FibrousGlass Insulation. Per the ASTM C 1511 test protocol (which is the sameas that used to assess commercial aerogel blanket insulators), samplesof the novel blanket have been submerged 5 inch (13 cm) below thesurface of water for 15 min. The novel final blanket absorbed less waterthan five percent of its own weight. The samples were then heated to600° F. (315° C.) for 24 hours. ASTM C1511 testing was repeated, andagain there was less than five percent water absorption by mass.

Preliminary tests showed good permeability to water vapor, better thanthat of aerogel-based materials.

In one embodiment, an improved hydrophobic insulation blanket isprovided that has an inorganic, textile-grade glass fiber structuredblanket/mat, and a hydrophobic polymer coating. Components of the finalblanket may also include: an opacifier and a relatively smaller quantityof hydrophobic-coated inorganic particles incorporated as a topcoat. Theflexible insulation blanket has excellent hydrophobic properties duringcontinuous long-term use to 600° F. (315° C.), or to 700° F. (370° C.)for short excursions, without the production of substantial amounts ofdust during manufacturing, installation, or use.

Properties of the novel final insulation blanket include: a) low thermalconductivity, b) ease of manufacture and application, c) no generationof substantial amounts of dust, d) ease of cutting and fabrication, ande) moldability. The novel insulation blankets are especially suited forhigh temperature uses (100° F. (40° C.) and above), for example for usein hydrocarbon processing, oil and gas production and refining, chemicalproduction, aerospace applications, appliances, marine, and automotiveapplications. The novel final blankets can easily be processed intofinished insulation parts, for example by compression molding or diecutting. They are ideal for OEM-specific applications requiring acombination of moldability, hydrophobicity, and high thermal insulationefficiency.

The novel final blanket can be made moldable by a suitable choice ofcomponents, and moldable embodiments can then readily be shaped/moldedin secondary processing. These embodiments can, for example, beprocessed into finished insulation parts using otherwise conventionalmethods such as compression molding and die cutting. Moldablecompositions are ideal for OEM applications requiring moldability,hydrophobicity, and thermal insulation up to 600° F. (315° C.).

The final blanket remains both insulating and hydrophobic at highertemperatures than existing aerogel products. Although aerogel-basedblankets can remain insulating at 600° F. (315° C.), the hydrophobiccomponents of existing aerogel-based blankets decompose at thattemperature, rendering the aerogel product much more hydrophilic. Bycontrast, the novel product remains both thermally insulating andhydrophobic up to 600° F. (315° C.) for long-term use, with short-termexcursions allowed to even higher temperatures.

The invention is a hydrophobic needle-felted insulation blanket having atextile-grade needle felted fiberglass blanket having a density in therange of 4 to 15 lb/ft′ (65 to 250 g/L); a uniform hydrophobicfluoropolymer disposed homogeneously throughout the textile grade needlefelted fiberglass blanket without creating a higher density ofhydrophobic fluoropolymer near edges of the textile-grade needle feltedfiberglass blanket, wherein the fluoropolymer has a melting point over550° Fahrenheit; and a non-decomposed hydrophilic opacifier uniformlydisposed through the textile grade needle felted fiberglass blanket thatreduces radiative heat flow through the finished blanket.

The finished hydrophobic needle-felted insulation blanket is (i)temperature stable up to 550° Fahrenheit, (ii) moldable, (iii) silicadust free, and thereafter retains a selected shape and the finishedblanket will not decompose, disintegrate, or lose structural integritywhen submerged in water.

The finished hydrophobic needle-felted insulation blanket has by weight:60%-95% glass fiber 2%-30% hydrophobic flouropolymer, and 0.1-10%non-decomposed hydrophilic opacifier.

In embodiments, the finished hydrophobic needle-felted insulationblanket is free of any residual hydrophilic compounds, including glassfiber sizing, and the surfactants that had previously been used toemulsify the fluoropolymer.

In embodiments, the textile-grade needle felted fiberglass blanket has:fibers are selected from the group consisting of E-glass fiber, C-glassfiber, T-glass fiber, S-glass fiber, textile-grade basalt fiber, carbonfiber, aramid fibers, and mixtures thereof; and wherein the diameters ofthe glass fibers are from 4 to 13 microns.

In embodiments, the finished blanket of has a thermal conductivity kmeasured as (Btu·in/hr-ft² F) of from about 0.26 at 75 F to about 1.18at 1050 F.

In embodiments, the opacifier comprises particles selected from thegroup consisting of: carbon black, graphite, graphene, titanium dioxide,iron oxides, silicon carbide, zirconium dioxide, and mixtures thereof;and wherein the opacifier comprises 0.1% to 10% of the finished blanketby weight.

In embodiments, the hydrophobic needle-felted insulation blanket has asuper-hydrophobic topcoat disposed on at least one surface of thefinished blanket.

The super-hydrophobic topcoat includes from 60% to 99% by mass based onthe total mass of the topcoat of second hydrophobic polymer consistingof polytetrafluoroethylene, from 0.1 to 10% by mass of silicone resinbased on the total mass of the topcoat, from 0.1 to 10% by mass of anopacifer based on the total mass of the topcoat, and from 0.1 to 20% ofhydrophobic inorganic particles by mass based on the total mass of thetopcoat.

In embodiments of the super-hydrophobic topcoat, the first and secondhydrophobic polymers may be the same or different; and wherein theinorganic particles comprise particles selected from the groupconsisting of silica aerogel, fumed silica, precipitated silica,synthetic amorphous silica, and mixtures thereof.

In other embodiments of the hydrophobic needle-felted insulationblanket, the super-hydrophobic topcoat disposed on at least one surfaceof the finished blanket; wherein the inorganic particles have a particlesize between 0.1 to 100 microns; wherein the inorganic particles have aspecific surface area of 100 m²/g or greater; and wherein the inorganicparticles comprise a hydrophobic surface and comprise from 1 to 25 wt %of the finished blanket by mass, wherein said hydrophobic surfacetreatment comprises dimethyl silyl, trimethylsilyl, or other alkylsilylmoieties.

In embodiments, the super-hydrophobic topcoat disposed on at least onesurface of the finished blanket has inorganic particles with a particlesize between 0.1 to 100 microns; and wherein the inorganic particleshave a specific surface area of 100 m²/g or greater; and wherein theinorganic particles comprise a hydrophobic surface and comprise from 0.1weight percent to 10 weight percent of the finished blanket by mass and0.1 weight percent to 20 weight percent by mass in the topcoat.

In embodiments, the finished hydrophobic needle-felted insulationblanket has the first hydrophobic polymer and the glass fibersinterspersed with one another with sufficient uniformity to form aflexible matrix and render the finished blanket hydrophobic attemperatures at least up to 315° C.

In embodiments, the finished hydrophobic needle-felted insulationblanket has a super-hydrophobic surface/topcoat containing a silicone,and wherein the silicone is di-alkyl silicone fluid used in the form ofaqueous emulsions with particle sizes from 100 nm to several μm. Thealkyl group having from 1 to 8 carbon atoms is methyl, phenyl, propyl,or a combination of these.

In embodiments, the finished hydrophobic needle-felted insulationblanket has fibers that are from 60% to 95% by mass of the finishedblanket.

In embodiments, the fluoropolymer is a compound selected from the groupconsisting of polytetrafluoroethylene, perfluoroalkoxy alkanes,fluorinated ethylene propylene, and mixtures thereof.

In embodiments, the dispersion through the finished blanket is achievedby a two step forced air processes which in the second step applies avacuum to the fabric pulling the elevated hot air through the blanketfabric quickly in just a few minutes.

In embodiments, of the finished hydrophobic needle-felted insulationblanket the uniform hydrophobic fluoropolymer is from 2 percent to 30percent by mass of the finished hydrophobic needle-felted insulationblanket. If a moldable product is desired, the concentration of lowmelting fluoropolymer can be from 0.1 percent to 25 percent by mass.

In embodiments, the invention is a thermal insulation composite thatcontains a textile-grade glass fiber insulating core, typically in theform of a blanket. The blanket is impregnated with a hydrophobicpolymer, and an opacifier. The glass fibers/filaments are coated with adispersion of a hydrophobic polymer, typically a fluoropolymer, using adispersion of a type otherwise known in the art. The fiberglasspreferably has a needle-felt construction, but other forms of fiberglassmay also be used. A fiberglass needle felt is produced from yarn byopening up a textile-grade fiberglass yarn into its constituent fibers,and stitching the fibers together with a needle loom, to make a feltblanket that is held together mechanically, rather than with anadhesive.

A preferred process for forming the novel blanket includes: (a) forminga dispersion of a hydrophobic polymer in a solvent with a surfactant(e.g., a dispersion of a fluoropolymer such as polytetrafluoroethylene),and may also include an opacifier; (b) repeatedly dipping and nippingthe needle-felted blanket into the fluoropolymer dispersion to form ahomogeneously wetted blanket; (c) evaporating water/solvent from the wetblanket by application of intense electromagnetic radiation (EMRad) toleave behind the hydrophobic polymer properly distributed throughout theblanket, including its interior; (d) decomposing hydrophilic residuesremaining from the former dispersion and from the original fiberglassmaterial, by heated air flow through the blanket (typical hydrophilicresidues thus removed can include, for example, sizing (starches) fromthe processed fiberglass, and surfactants from the fluoropolymerdispersion formulation), (e) spraying or otherwise coating an additionalhydrophobic layer onto one or more outer surfaces of the blanket to makethe material super-hydrophobic, (f) drying the surface coating,typically by conventional surface heating methods. Cut edges typicallyare not further coated, although they could be.

Surprisingly, the method used two different steps to evaporatewater/solvent from the wet blanket (step (c) in the description of theprior paragraph) is very important. Conventional drying techniques suchas forced-air drying, convection heating, radiant heating, and infraredheating were found to be unsuitable, and to lead to inferior products.When these other heating methods were employed, most of the hydrophobicpolymer evidently migrated to the surface of the blanket, which left theinterior of the blanket relatively devoid of hydrophobic polymer, andrendered the interior susceptible to absorbing water. Although theseother drying techniques may be appropriate for other processes, such ascoating relatively thin woven fabrics with fluoropolymers, surprisingly,that they worked poorly with thicker blankets such as fiberglass needlefelts, thicker than about 0.25 inch (6 mm).

Surprisingly, the manner of drying in step (c) is highly significant. Inparticular, that drying by electromagnetic radiation (EMRad), preferablyradio frequency or microwave radiation, unlike other drying techniques,leaves the hydrophobic polymer more evenly dispersed throughout thefiberglass blanket, and results in a product with superiorhydrophobicity following solvent evaporation. However, EMRad dryingalone is generally not sufficient to remove all water/solventefficiently; thus the EMRad drying step should be followed by a requiredsequential further drying step, such as forcing hot air through theEMRad-dried blanket. Provided that most of the solvent has previouslybeen evaporated by the EMRad step, a further drying/heating step by adifferent means does not result in maldistribution of the hydrophobicpolymer.

To achieve the required hydrophobic character, residual hydrophiliccomponents should be removed—e.g., sizing (starch) coating on thefiberglass, and surfactant derived from the fluoropolymer dispersion.This decomposition and removal is conveniently accomplished by thesecond heating step, typically with forced air at 400° F. to 650° F.(205° C. to 345° C.).

In one embodiment, a hydrophobic insulation blanket in accordance withthe present invention contains the following ingredients at theindicated proportions, based on percentage by mass of the finishedblanket:

Component Range(%) Preferred Range (%) Glass fiber 60-95  80-90Hydrophobic polymer 2-30  5-25 Hydrophobic inorganic particle 0-10 0-5Opacifier 0-10 0-5

In embodiments, the textile-grade glass fiber may, for example, beE-glass fiber, C-glass fiber, ECR-glass fiber, S-glass fiber, high Si0 2percentage fiber, or blends of these fibers, long enough and strongenough to create a durable, needle-felted blanket. The blanket ispreferably a needle-felted, textile-grade fiberglass blanket having adensity in the range of 4 to 15 lb/ft3 (65 to 250 g/L), more preferablyin the range of 6 to 12 lb/ft3 (100 to 200 g/L). The glass fiberpreferably has a minimum temperature rating of at least 1200° F. (650°C.), and more preferably up to 1800° F. (980° C.). The diameter of theglass fibers is a matter of choice, and may for example be in the rangeof 4 to 13 microns, preferably in the range of 6 to 11 microns. Fiberlength is also a matter of choice, provided that the fibers are longenough and strong enough to create a durable, needle-felted blanket; thefiber length may for example be between 0.2 to 6 inches (0.5 to 15 cm),and is preferably 2 to 5 inches (5 to 13 cm).

Alternatively, a needle felted blanket manufactured from basalt-based,textile-grade fibers otherwise known in the art could be used inpracticing the invention. Again, the basalt-derived fibers should belong enough and strong enough to create a durable, needle-feltedblanket.

The hydrophobic polymer is preferably a fluoropolymer. Preferably, thehydrophobic polymer is temperature-stable at least up to 600° F. (315°C.). The fluoropolymer may be applied as a water-based or organicsolvent-based dispersion. Examples of hydrophobic polymers that can beused in the present invention include, but are not limited to,polytetrafluoroethylene (PTFE), perfluoroalkoxy alkanes (PFA),fluorinated ethylene propylene (FEP), and blends of these polymers.

The product can be made moldable by employing a mixture offluoropolymers with substantially different melting points. For example,including a fraction of a lower melting point fluoropolymer, such as FEPor PFA with a melting point below 600° F. (315° C.), in a compositioncontaining a larger fraction of a higher-melting polymer can enhanceoverall moldability. The low-melting fluoropolymer is between 0.1% and90% of the total fluoropolymer by mass, and is between 0.1% and 25% ofthe finished blanket by mass.

In embodiments, hydrophobic inorganic filler can be combined withfluoropolymer dispersion, can be used to form a super-hydrophobic topcoat on one or more outer faces of the blanket, which has otherwise beenproduced as described above. Examples of hydrophobic inorganic fillersthat can be used in such an outer coating include, but are not limitedto, silica aerogel, fumed silica, precipitated silica, micron sizesynthetic amorphous silica, and other fumed oxides—in each case,surface-treated to render the materials hydrophobic. A preferredhydrophobic inorganic particulate material is a silica aerogel or fumedsilica that has been surface-modified with one or more alkylsilylgroups, such as with dimethyl silyl or trimethylsilyl groups, to makethe particles water-resistant. The surface area of the hydrophobicinorganic particulate material can be greater than 100 m²/g, preferablygreater than 150 m²/g. The particle size of the hydrophobic inorganicparticulate material can be in the range of 0.1 to 100 microns,preferably in the range of 0.5 to 50 microns.

An infrared opacifier is included to reduce radiative contributions tothermal conduction, especially at higher temperatures. Examples ofopacifiers include, but are not limited to, carbon black, graphite,graphene, titanium dioxide (TiO2), iron oxides (e.g., Fe2O3 or Fe3O4,),silicon carbide (SiC), zirconium dioxide, and their mixtures. Theparticle size of the opacifier can be in the range of 0.1 to 100microns, preferably 1 to 20 microns.

Preferred process of making hydrophobic blanket: In one embodiment a wetfiberglass blanket is impregnated with a hydrophobic fluoropolymerdispersion in water, and the wetted blanket is initially dried by EMRadheating, specifically radio frequency (RF) or microwave heating,followed by a second heating step using forced hot air. Other methods ofheating have also been tested (particularly for the initial dryingstep), but other heating methods produced quite unsatisfactory results,apparently because they induced (or allowed) migration of fluoropolymerto the outer surface of the fiberglass, leaving the inner portionlargely uncoated and far more susceptible to absorbing water.Surprisingly, the use of EMRad (radio frequency or microwave)heating—unlike the other heating methods—resulted in a uniform polymerdistribution throughout the blanket, without significant migration ofthe fluoropolymer, rendering the entire thickness of the blankethydrophobic. EMRad alsohas the benefits of rapid drying time, fastproduction/manufacturing line speeds, compatibility with a continuousprocessing mode, consistent final moisture levels, and lower dryingtemperatures as compared to common radiant or convection heatingmethods.

In embodiments, the hydrophobic needle-felted insulation blanket is madeby a process that is illustrated schematically in the FIGURE. In theFIGURE, the identifying numerals refer both to the steps of the embodiedprocess, and to the apparatus for carrying out the corresponding step:

(Step 1) Needle-felted fiber glass blankets of a chosen density aredipped/submerged into a wetting tank containing a fluoropolymerdispersion. (Fluoropolymer dispersions in water, or water-alcohol mixedsolvents are well-known in the art.) The wetted blanket is nipped (orcompressed) to reach a target wet weight, preferably an increase of50%-200% over the weight of the raw dry blanket. The dipping and nippingstep may be repeated as necessary to achieve uniform wetting at thedesired density. (Step 2) The wetted, nipped blanket is then transferredto an EMRad drying oven, where the bulk of the solvent is evaporated.The percentage of solvent evaporated at this stage should be at least50%, preferably at least 70%, and most preferably at least 90%. (Step 3)The EMRad-dried blanket is then transferred to high-temperature, hot airflow-through drying equipment for further drying/evaporation of solvent,and also for the thermal decomposition and removal of residualhydrophilic compounds, such as glass fiber sizing (starch), and thesurfactants that had previously been used to emulsify the fluoropolymer.The temperature of the heated air in this step 3 is in the range 400° F.to 650° F. (205° C. to 345° C.), preferably 500° F. to 600° F. (260° C.to 315° C.). (Above 630° F. (330° C.), PTFE sinters (melts), which isundesirable in this process.) The hot air flow-through drying is rapidand economical. (Step 4) The blanket is given a super-hydrophobic topcoat on one or more surfaces, where the top coating comprises a film ofa fluoropolymer dispersion that further contains hydrophobic inorganicparticles (e.g., hydrophobic silica coated with a fluoropolymer). Thiscoating is preferably applied to the top and bottom surfaces of theblankets. Cut edges are generally not coated, although they could be. (Asurface is considered “super-hydrophobic” when its contact angle with awater droplet is greater than 150°. Such measurements may be made, forexample, in accordance with ASTM D7334.) (Step 5) The coated surfacesare impingement-dried in a convection oven at a temperature of 400 to650° F. (205° C. to 345° C.).

Fluoropolymer Dispersion. The fluoropolymer dispersion can includesolvent, one or more fluoropolymers, an opacifier, and a surfactant. Thepreferred solvent can be polar, and is preferably a mixture of water anda low molecular weight alcohol. The percentage of alcohol in the mixturecan be in the range of 0 to 99 vol %, preferably 5 to 90 vol %. Alcoholsthat can be used include, but are not limited to, methanol, ethanol, andisopropanol. The concentration of hydrophobic fluoropolymer in thedispersion can be in the range of 0.1 to 60 wt %, preferably 7 to 20 wt%. The concentration of surfactant can be in the range of 0.1 to 10 wt%, preferably 1 to 8 wt %. Commercial fluoropolymer dispersions aretypically sold with surfactants already incorporated; it will generallysuffice to use such mixtures as provided by the manufacturer without theneed to add a further surfactant.

Dispersion Topcoat: The preferred surface coating dispersion includes ahydrophobic polymer (preferably the same hydrophobic polymer used insoaking the blanket), IR opacifier, hydrophobic inorganic particles, anda suitable wetting agent. The wetting agent can be a surfactant having alow boiling point. Typical wetting agents can be anionic or nonionicsurfactants. A preferred wetting agent is capable of volatilizing ordecomposing, so that it can be removed during the drying step to restorethe hydrophobicity of the hydrophobic polymer. (Any residual wettingagent remaining on the surface of the particles could reducehydrophobicity of the blanket.) Removal of the wetting agent can be byvolatilization, with or without decomposition. Wetting agents(surfactants) that can be used include, but are not limited to, thevarious ether amine oxides and ethoxylated alcohols known in the art.The concentration of hydrophobic polymer particles in the dispersion canbe in the range of 0.1 to 30 wt %, preferably 1 to 15 wt %. Theconcentration of hydrophobic inorganic particles can be in the range of0 to 10 wt %, preferably in the range of 0 to 5 wt %. The concentrationof the wetting agent (surfactant) in the dispersion can be in the rangeof 0.01 to 10 wt %, preferably 0.1 to 5 wt %. The concentration ofopacifier can be in the range of 0 to 10 wt %, preferably 0 to 5 wt %.

The hydrophobic textile-grade fiberglass blanket of the presentinvention can be used for a variety of purposes, including use as athermal insulating material for process equipment, pipe or pipelineenergy conservation, process control reliability, upstream oil recovery,pipe-in-pipe applications, insulation for aircraft, insulation forautomobiles and trucks, insulation for marine craft, buildinginsulation, aerospace insulation, clothing insulation, footwearinsulation, and the like. The present invention can be used in nearlyall applications where aerogel insulation blankets are currently used,as well as in applications where aerogels are not generally used due totheir cost or because they generate dust. Blankets in accordance withthe present invention can, however, be manufactured much thicker thancan aerogel blankets. Aerogel blankets are typically 4 to 15 mm thick,although it might be possible to custom-manufacture thicker aerogelblankets for specific purposes. To date, mats in accordance with thepresent invention have been prepared in thicknesses up to 1.25 inches(32 mm), based primarily on the thickness of the rolled “raw” fiberglassblankets as originally received from the manufacturer.

The preparation of thicker mats in accordance with the present inventionis expected to be straightforward, using thicker “raw” fiberglassblankets as starting materials, although to date thicker blankets havenot yet been tested.

Further details and explanation of the present invention may be found inthe following examples, which are given by way of illustration and notlimitation:

EXAMPLES Example 1

A hydrophobic insulation blanket was made from fiberglass needle blanketand PTFE. A uniform dispersion for impregnation (first dispersion) wasmade in a 1-quart (1 L) container by adding 0.1 lb (45 g) of PTFEparticles in a surfactant dispersion (Laurel AD-10, Laurel Products,LLC., Elverson, Pa.) with 0.5 lb (225 mL) of water, and agitating at 750rpm for about 10 min.

Lewco fiberglass needle felts (Lewco Specialty Products Inc., BatonRouge, La.) with a density of 10 lb/ft3 (0.15 kg/L) and a thickness of0.5 inch (1.3 cm) were completely dipped/soaked in the PTFE dispersion.The soaked blankets were immediately nipped/pressurized (i.e.,pressure-squeezed between rollers) to reach a total wet weight of 2.0times the weight of the raw dry blankets, and the blankets were thentransferred to a microwave oven for 15 to 60 min. The mass of water lostin the microwave oven was about 90 wt %. The blankets were thentransferred to forced hot air (laboratory) drying equipment for dryingat 550° F. (290° C.).

This example was conducted on a laboratory scale. On an industrialscale, the blankets will be moved by conveyor belt through the variousprocess steps, as shown schematically in the FIGURE as a continuousprocess.

The final blanket was then surface-coated with a second dispersion. Thesecond dispersion was made in a I-quart (1 L) container by adding 0.1 lb(45 g) of PTFE particles in a surfactant dispersion (Laurel AD-10,Laurel Products, LLC) with 0.5 lb (225 mL) of water; 0.01 lb (4.5 g) ofsilica aerogel that had been surface-modified with trimethyl groups,average particle size of about 10 μm, (JIOS AeroVa® Aerogel, JIOSAerogel Corporation, Gyeonggi-do, Korea); and 0.01 lb (4.5 of SurfynolTG (Air Products and Chemicals, Inc., Allentown, Pa.) surfactant; andagitating at 1500 rpm for about 10 min. The dispersion was applied byspraying onto both the top and bottom surfaces of the blanket. Theblanket was then dried in an impingement convection oven at about 550°F. (290° C.) for approximately 4 min. Alternatively, one could useinfrared drying, or a combination of impingement convection and infrareddrying.

The resulting final blanket was very flexible. The thermal conductivityof the finished blanket was measured according to the procedures ofprotocol ASTM Cl 77 in effect on the filing date of this application.The thermal conductivity (k value, Btuin/hr·ft2·° F.) at differenttemperatures is shown in Table 1. Surprisingly, the PTFE actuallyimproved the thermal insulation properties of the needled bondfiberglass blanket, albeit slightly. This result was unexpected, becausePTFE's thermal insulation properties are inferior to those of needledbond fiberglass blanket, and therefore inferior thermal properties wouldhave been expected by incorporating PTFE.

TABLE 1 (Imperial Units). Thermal conductivity (k) of hydrophobicfiberglass blanket (HFB) and untreated fiberglass needle felts (FNF),determined per ASTM Cl 77 effective on the filing date of thisapplication. Temperature (° F.) 75 300 500 700 900 1050 K HFB 0.26 0.370.47 0.62 0.95 1.18 (Btu · in/hr-ft 2 0 F.) FNF 0.26 0.36 0.49 0.65

TABLE 1 (Metric Units). Thermal conductivity (k) of hydrophobicfiberglass blanket (HFB) and untreated fiberglass needle felts (FNF),determined per ASTM Cl 77. Temperature (° C.) 24 149 260 371 482 566 HFB0.037 0.053 0.070 0.09 0.137 0.170 k (Watt/m · ° K) FNF 0.037 0.0520.070 0.094

The water absorption of the finished product was measured according toASTM C 1511 which as in effect as of the filing date of thisapplication, to be less than 5 wt % (per the results of testing by anindependent laboratory; our own tests had showed water absorptionbetween 1.5 wt % and 3.2 wt %).

Example 2

Example 2 (which was unsuccessful) actually preceded Example 1 (whichwas successful). Example 2 can be used (in hindsight) to illustrate theeffect that the manner of solvent evaporation has on the hydrophobicityof the produced blanket, as shown in Table 2. The procedures werelargely the same as Example 1—with the principal exception that no EMRadoven was used. Water was instead evaporated from the wetted blanket witha traditional, convection oven. The final blanket produced in thismanner absorbed more than 5 wt % water, and thus did not satisfy theASTM C 1511 test protocol. Conventional oven heating evidently resultedin a maldistribution of the PTFE dispersion in the produced blankets.Most of the PTFE apparently migrated to the (outer) surfaces of theblanket, leaving the center of the blanket largely devoid of hydrophobiccomponents-meaning that the center readily absorbed water. By contrast,the blanket produced by EMRad drying.

(Example 1) had a much more uniform distribution of hydrophobic polymer,and this blanket absorbed less than 5 wt % water. In Table 2, Samples 1and 2 were from Example 2; and Samples 3 and 4 were from Example 1:

TABLE 2 Effect of manner of solvent evaporation from the wet blankets.Sample Drying method Oven temperature Water absorption 1 Conventionaloven 590° P (310° C.) 8.3 wt % † 2 Conventional oven 630° P (330° C.)10.2 wt % † 3 Microwave N/A 3.1 wt % 4 Radio frequency N/A 2.9 wt % †These two values are higher than the values we had originally measured,6.2% and 7.6%. The higher values in the later measurements reported inTable 2 resulted from retesting, using materials with cut edges. Thehigher water absorption by cut edges reflects the practical problem thatcut edges increase the potential for a hydrophilic interior to beexposed to water, and to absorb water.

Example 3

Procedures were the same as in Example 1, except that blankets were madefrom fiberglass needle felts of differing densities and thicknesses.This Example examined the effect of the density and thickness of the rawblanket on the hydrophobicity of the produced blanket. Water absorptionby the resulting blankets is summarized in Table 3, in which thereported values were measured in accordance with ASTM C 1511. Allsamples met the ASTM C 1511 standard of absorbing less than 5 wt %water, meaning that all were effective as hydrophobic fiberglassinsulating blankets.

TABLE 3 Effect of density and thickness of hydrophobic fiberglass needlefelts. Sample Density Thickness Water absorption 1. 7 lb/ft³ (110 g/L)0.3 in (8 mm)  3.7 wt % 2. 7 lb/ft³ (110 g/L) 0.5 in (13 mm) 2.9 wt % 3.10 lb/ft3 (160 g/L) 0.5 in (13 mm) 2.8 wt % 4. 10 lb/ft3 (160 g/L) 0.6in (15 mm) 3.3 wt % 5. 10 lb/ft3 (160 g/L) 0.8 in (20 mm) 2.0 wt % 6. 12lb/ft3 (190 g/L) 0.9 in (23 mm) 1.7 wt %

These data showed that the final hydrophobicity of a processed blanketwas largely independent of its density or thickness.

Example 4

Procedures were the same as in Example 1, except that blankets were madewith a different concentration of hydrophobic fluoropolymer in thedispersion. This Example examined the effect that the hydrophobicfluoropolymer concentration in the dispersion had on the hydrophobicityof the produced blanket. The water absorption of the resulting blanketsis summarized in Table 4.

TABLE 4 Effect of concentration of hydrophobic fluoropolymer m thedispersion. Sample PTFE concentration in the dispersion Water absorption1 20 wt % 4.0 wt % 2 10 wt % 2.8 wt % 3  7 wt % 3.0 wt % 4  5 wt % 3.2wt %

The results in Table 4 indicated that the PTFE concentration (over therange 5 wt % to 20 wt %) in the dispersion did not strongly affect thewater absorption properties of the finished blanket, albeit there wassome variation. All samples tested met the criteria of ASTM C 1511. Inother results (not shown), 40% PTFE loading resulted in higher waterabsorption than did lower levels of PTFE. Likewise, 10% gave betterresults than 20%. The lower water absorption at lower levels of PTFE wasquite surprising. The 10% level is considered optimal, and is lessexpensive than higher loadings. Even at 5% the water absorption is stillquite low, although it was not as good as at 10%. Also, lower levels ofPTFE had slightly lower thermal conductivity than higher levels, perhapsbecause there is less mass to conduct heat.

Example 5

Procedures were the same as in Example 1, except that the blankets haddifferent wet weights after the dipping/nipping cycles. This Exampleexamined the effect of the loading concentration of hydrophobicfluoropolymer on the hydrophobicity of the produced blanket. The higherthe weight of the wet blanket, the greater was the loading of thehydrophobic fluoropolymer in the produced blanket. After drying, theproduced blankets were tested per ASTM C1511. The water absorptions ofthe blankets are summarized in Table 5. All samples met the ASTM C 1511standard, i.e., the fluoropolymer loading levels used in this series ofexperiments (between 8 wt % to 14 wt %) were effective in makinghydrophobic fiberglass insulating blankets.

TABLE 5 Effect of weight of wet blanket after repeated dipping/nippingon water absorption by the finished blankets, per ASTM Cl511.Fluoropolymer Increased weight of weight in final Water absorption ofSample wet blanket dry blanket finished blanket 1 55% 8.0% 2.9 wt % 273% 9.5% 4.0 wt % 3 97% 11.5% 3.0 wt % 4 119%  13.2% 3.2 wt % 5 125% 13.7% 2.0 wt %

Example 6

Procedures were the same as in Example 1, except that differentpercentages of solvent were removed from the wet blankets by EMRaddrying. This Example examined the effect of the degree of solventremoval by the initial EMRad drying step on the hydrophobicity of theproduced blanket. The observations showed that the more solvent that wasremoved from the wet blanket by EMRad drying, the more uniform appearedto be the distribution of hydrophobic fluoropolymer throughout theblanket. The water absorption per ASTM C1511 for the resulting blanketsis summarized in Table 6. All samples except Sample 1 met the ASTM C1511 standard. Based on these observations, we concluded that it ispreferred to remove 70% or more of the solvent by EMRad; and that,within the limits of what is practical and economical in a particularsetting, it is preferred to remove as much solvent as reasonablyfeasible in the initial EMRad drying step.

TABLE 6 Effect of degree of solvent removal by EMRad drying on waterabsorption of finished blanket. Weight loss of solvent by Waterabsorption per ASTM Cl511 Sample EMRad drying Standard 1. 53%  .0 wt %2. 76% 4.3 wt % 3. 88% 3.7 wt % 4. 92% 2.8 wt %

Example 7

Procedures were the same as in Example 1, except that the blankets wereprepared with various topcoats. This Example examined the effect of thecomposition of the top coat on the hydrophobicity of the producedblanket. The water absorptions of the resulting blankets are summarizedin Table 7. Samples without a top coat, or with a 100% PTFE top coat hadgreater than 5% water retention, while samples with a top coatcontaining one of various hydrophobic inorganic particles and PTFE hadless than 5% water retention. Applying a top coat with a combination ofa hydrophobic inorganic particle and PTFE is preferred, as it producessuper-hydrophobic surface performance; water adhesion on the surface ofthe blankets is drastically reduced. The wettability of a solid surfaceis determined by the chemical composition and geometrical structure(“roughness”) of the surface. Without wishing to be bound by thishypothesis, the inventors believe that the inorganic particles impartmulti-scale roughness to the blanket surface; and the hydrophobicpolymer provides high contact angles for water droplets; the result ofthe combination being a low overall roll-off angle for water on thesurface.

TABLE 7 Effect of the composition of the top coat. Samples Compositionof top coat Water retention 1 No top coat 10.0 wt %  2 100% PTFE 6.0 wt% 3 90% PTFE + 10% aerogel 2.7 wt % 4 90% PTFE + 10% fumed silica 4.0 wt% 5 90% PTFE + 10% precipitated silica 4.9 wt % 6 80% PTFE + 20%precipitated silica 2.3 wt %

Example 8

Procedures were the same as in Example 1, except that after the topcoathad been applied, the resulting blanket was heated for 24 hours at 550°F. (290° C.) with an impingement convection oven. The resulting blanketsatisfied the ASTM C 1511 standard, and was super-hydrophobic. (Likelythe heating could also be carried out for a shorter time and stillproduce a super-hydrophobic blanket; the heating time will be optimizedin future testing.) The resulting blanket was then further aged for 24hours at 600° F. (315° C.), 650° F. (345° C.), or 700° F. (370° C.).This Example examined the effect of aging for 24 hours at varioustemperatures on the hydrophobicity of the produced blanket. Results areshown in Table 8. The results indicated that all aged samples met ASTM C1511, and that the blankets remained hydrophobic at least up to an agingtemperature 700° F. (370° C.) for a short-term (24-hour) exposure.

TABLE 8 Effect of 24 hour-aging temperature on water retention. SampleTemperature Water Retention 1. 600° F. (315° C.) 2.5 wt % 2. 650° F.(345° C.) 3.2 wt % 3. 700° F. (370° C.) 4.5 wt %

Example 9

Samples of the novel insulation blanket were tested by an independent,certified laboratory using the test criteria of ASTM Cl 77 (StandardTest Method for Steady-State Heat Flux Measurements and ThermalTransmission Properties by Means of the Guarded-Hot-Plate Apparatus).Results of the independent testing are given in Table 9. Included inTable 9 for comparison are published thermal conductivity measurementsfor other, commercially available insulation materials. The resultsindicated that at or below 700° F. (370° C.), the novel hydrophobicfiberglass blanket had better thermal insulation properties than do mostcommercially available insulation materials, except for the aerogelblankets and microporous silica blankets. Aerogel blankets have slightlybetter insulation properties; however aerogel blankets are moreexpensive, and they tend to generate unwanted dust during installationand use.

TABLE 9 (Imperial units). Thermal Conductivity of the novel hydrophobicfiberglass (E glass) blanket (HFB); an in situ sol-gel-formed aerogelblanket (AG); expanded perlite block (EP); calcium silicate block (CS);and mineral wool (MW) Thermal Conductivity, k, BTU-in/hr-ft2-° F.Temperature (° F.) HFB* AG** MW** CS** EP** 75 0.26 0.16 0.24 0.41 0.48300 0.37 0.21 0.36 0.50 0.59 500 0.47 0.28 0.53 0.60 0.69 700 0.62 0.390.75 0.71 0.80 900 0.95 0.50 1050 1.18 0.62 *Thermal conductivityresults per ASTM C 177, testing by an independent third partylaboratory. **Thermal conductivity figures from industry-supplied data(e.g. insulation thickness calculators, manufacturer's data sheet, orother reference sources)

TABLE 9 (Metric units). Thermal Conductivity of the novel hydrophobicfiberglass (E glass) blanket (HFB); an in situ sol-gel-formed aerogelblanket (AG); expanded perlite block (EP); calcium silicate block (CS);and mineral wool (MW) Thermal Conductivity, k, W/m-° K Temperature (°C.) HFB* AG** MW** CS** EP** 24 0.037 0.023 0.034 0.059 0.069 149 0.0530.030 0.052 0.072 0.085 260 0.067 0.040 0.076 0.086 0.099 370 0.09 0.0560.108 0.102 0.115 482 0.137 0.072 566 0.170 0.089 *Thermal conductivityresults per ASTM C 177, testing by an independent third partylaboratory. **Thermal conductivity figures from industry-supplied data(e.g. insulation thickness calculators, manufacturer's data sheet, orother reference sources)

Example 10

Moldable hydrophobic insulation blankets were made from fiberglassneedle blanket, PTFE, and fluorinated ethylene propylene (FEP); or fromfiberglass needle blanket, PTFE, and perfluoroalkoxy alkanes (PFA); ineach case, with a super-hydrophobic topcoat. Procedures were the same asin Example 1, except that the blankets were made from PTFE, PFA, FEP, ormixtures. A super-hydrophobic topcoat was applied in all cases. Theproduced blankets were tested for water absorption per ASTM C1511. Theresults are summarized in Table 10.

TABLE 10 Effect of composition. Sample PTPE PPA PEP Water absorption 110 wt % 0 0 3.0 wt % 2 10 wt % 0 10 wt % 3.6 wt % 3 10 wt % 10 wt % 03.9 wt %

Examples 11-14

Samples of the blankets were hot-compressed in a mold, followed bycooling down. “Moldability” was assessed by processing or pressing ablanket into a desired shape, such as a tube or a pan. Blankets werewrapped around a metal tube, heated to 600° P (315° C.) for 15 min, andcooled to room temperature. The shapes of three molded samples are shownin a photograph that may be viewed in the disclosure of priorityapplication 62/512,385 (but that is not reproduced here). Samples 2 and3 were found to have a stable shape, indicating that the addition of PPAor PEP to PTPE increased the moldability of the blankets. Sample 1 didnot retain its shape as well as did the other two.

A blanket having the same composition as sample 2 was also molded into apan shape. Two household metal kitchen baking pans were used as themolds, each 4″×10″×6″ (10 cm×25 cm×15 cm), one pan as the inside moldand one pan as the outside mold. The molds with blanket were heated to600° P (315° C.) for 20 min, and cooled to room temperature. The formswere then removed, and the material was trimmed to 4″×10″×2″.

The shape of blanket was altered by the molding step, and the alteredshape was maintained thereafter. Accelerated aging tests were carriedout by placing molded pans of different formulations in a 600° P (315°C.) oven for 30 minutes. The same samples, before and after heating at600° P (315° C.), are shown in photographs that may be viewed in thedisclosure of priority application 62/512,385 (but that are notreproduced here). The pans made from Samples 2 and 3 were stablefollowing the accelerated heating test, indicating that the addition ofPPA or PEP to PTPE increased the moldability of the blankets. Sample 1,PTPE only, did not retain its shape as well as did the others. Samples 2and 3 were weighted with a steel plate for 30 minutes after heating andcooling. The steel was 12 inches×6 inches×0.25 inches (25 cm×12 cm×0.6cm). Both the FEP- and PFA-containing formulations held their shapeafter cooling, even after the application of the additional weight.

In another test a moldable blanket formulated from sample 2, Table 10was shaped into a rectangular bowl or pan. One inch of water was pouredinto the molded blanket bowl, and allowed to stand for three months.Additional water was added from time to time to compensate forevaporation, to maintain the depth of the water at about one inchthroughout the test. No water leaked, at least through the end of thethree-month trial. The insulation blanket was thus demonstrated to beboth moldable and hydrophobic. This rectangular bowl is shown in aphotograph that may be viewed in the disclosure of priority application62/512,385 (but that is not reproduced here).

Definitions: For purposes of this specification and the claims,“hydrophobic,” “hydrophobicity,” and like terms, when used in referenceto a composite material, mean that the material will, when submerged 5inches (13 cm) below the surface of deionized water for 15 minutes at25° C. and 1 atmosphere ambient air pressure, absorb five percent (5.0%)or less of its own mass in water. Further, a “hydrophobic” material willnot meaningfully dissolve, decompose, disintegrate, or lose structuralintegrity when submerged in water under these conditions.

When used in reference to an individual subcomponent, or in reference toa microscopic composite (e.g. a surface-modified aerogel particle),rather than to a macroscopic composite as a whole, the term“hydrophobic” is not given any special definition herein, and insteadthe word “hydrophobic” in those contexts should be understood as itwould normally be understood by persons of ordinary skill in the art.

For purposes of this specification and the claims, the term “composite”and like terms refer to an engineered, solid-phase material made fromtwo or more constituent materials having significantly differentphysical or chemical properties, in which the constituents remainseparate and distinct on a macroscopic level within the finished,solid-phase structure. The engineered materials produced in the Examplesdescribed herein, containing fiber glass, polymers, and othercomponents, are examples of “composite” materials.

For purposes of the specification and claims, when a process isdescribed as comprising certain “sequential” steps, the designation“sequential” indicates that the listed steps are performed in the orderdescribed. For a continuous process, one in which different processsteps are carried out simultaneously on different portions of afiberglass blanket as the blanket is pulled or transported through aseries of stations on a process line or assembly line, the steps areconsidered to be “sequential” for purposes of the specification andclaims if the steps are carried out in the designated order with respectto a small portion of the fiberglass blanket as the small portiontraverses the series of stations on the line; notwithstanding that someor all steps may be occurring on other portions of the blanketsimultaneously.

A “thermal insulator” is a material with a thermal conductivity, k, lessthan 1.00 BTU-in/hr-ft2-° F. (0.14 Watt/m° K) for at least sometemperatures between 75° F. and 700° F.

The term “super hydrophobic topcoat” refers to a topcoat that will notabsorb water any more 0.1 wt % to 5 wt % based on the total finishedblanket weight.

While these embodiments have been described with emphasis on theembodiments, it should be understood that within the scope of theappended claims, the embodiments might be practiced other than asspecifically described herein.

What is claimed is:
 1. A composite hydrophobic insulation textilecomprising glass fibers and a first fluoropolymer; wherein said firstfluoropolymer and the glass fibers are interspersed with one anotherwith sufficient uniformity to render the composite hydrophobicinsulation textile as hydrophobic insulation and is temperature stableup to 600 degrees Fahrenheit and comprises 60-90% glass fiber, 2-30%hydrophobic polymer and 1-10% hydrophobic inorganic particles.
 2. Thecomposite hydrophobic insulation textile of claim 1, wherein thecomposite does not release dust when handled or when in use.
 3. Thecomposite hydrophobic insulation textile of claim 1, wherein thecomposite hydrophobic insulation textile is a thermal insulator, with athermal conductivity k less than 0.14 Watt/m° K for at least sometemperatures between 25° C. and 370° C.
 4. The composite hydrophobicinsulation textile of claim 1, wherein the composite hydrophobicinsulation textile additionally comprises a super-hydrophobic topcoat onat least one surface of said composite; wherein said super-hydrophobictopcoat comprises a mixture of a second fluoropolymers and inorganicparticles; wherein said first and second fluoropolymers may be the sameor different; and wherein said inorganic particles comprise particlesselected from the group consisting of silica aerogel, fumed silica,precipitated silica, synthetic amorphous silica, and mixtures thereof;wherein said inorganic particles have a particle size between 0.1 to 100microns; wherein said inorganic particles have a specific surface areaof 100 m2/g or greater; and wherein said inorganic particles comprise ahydrophobic surface treatment.
 5. The composite hydrophobic insulationtextile of claim 4, wherein the hydrophobic surface treatment comprisesdimethyl silyl, trimethylsilyl, or other alkylsilyl moieties.
 6. Thecomposite hydrophobic insulation textile of claim 1, wherein thecomposite hydrophobic insulation textile additionally comprises aninfrared opacifier that reduces radiative heat flow; wherein saidinfrared opacifier comprises particles selected from the groupconsisting of carbon black, graphite, graphene, titanium dioxide, ironoxides, silicon carbide, zirconium dioxide, and mixtures thereof;wherein said infrared opacifier comprises 0.1% to 10% of said compositehydrophobic insulation textile by mass.
 7. The composite hydrophobicinsulation textile of claim 1, wherein the glass fibers comprise aneedle felt fiberglass blanket.
 8. The composite hydrophobic insulationtextile of claim 1, wherein the glass fibers are selected from the groupconsisting of E-glass fiber, C-glass fiber, T-glass fiber, S-glassfiber, textile-grade basalt fiber, and mixtures thereof; and wherein thediameters of said glass fibers are between 4 and 13 microns.
 9. Thecomposite hydrophobic insulation textile of claim 1, wherein the glassfibers are between 60% and 95% of said composite hydrophobic insulationtextile by mass.
 10. The composite hydrophobic insulation textile ofclaim 1, wherein the first fluoropolymer comprises a compound selectedfrom the group consisting of polytetrafluoroethylene, perfluoroalkoxyalkanes, fluorinated ethylene propylene, and mixtures thereof; andwherein said first fluoropolymer is between 2% and 30% of said compositehydrophobic insulation textile by mass.
 11. The composite hydrophobicinsulation textile of claim 10, wherein the first fluoropolymeradditionally comprises at least one additional, low-meltingfluoropolymer with a melting point below 315° C.; wherein saidlow-melting fluoropolymer is between 0.1% and 25% of said compositehydrophobic insulation textile by mass; and wherein said low-meltingfluoropolymer improves the ability to mold said composite hydrophobicinsulation textile into a selected shape that is retained after molding.12. The composite hydrophobic insulation textile of claim 11, whereinthe composite hydrophobic insulation textile is moldable, or wherein thecomposite hydrophobic insulation textile has been molded into andthereafter retains a selected shape.